Unit 5 - Biotechnology Flashcards
What is Forward Genetics?
studying a phenotype to understand the genotype
What is Reverse Genetics?
studying a genotype to undertand reverse genetics
(if you have a known gene, edit the gene, then see what changes occur in the organism, you can undertstand what the gene does)
GMO
Genetically Modified Organisms
plasmids
extrachromosomal DNA
Selective breeding is a way to make a _____.
GMO
What did Boyer & Cohen do in 1973?
Used RECOMBINANT DNA TEHCNOLOGY to create kanamyacin-resistant bacteria.
Explain the steps used in Recombinant DNA Technology for a bacteria.
- Isolate a plasmid.
- Cut the plasmid open.
- Insert new gene into the open plasmid.
- Rejoin ends of the plasmid with the new gene.
–> recombinant DNA - Insert the upgraded plasmid into bacteria so that the genes can be expressed.
What is Recombinant DNA?
DNA containing genes from different species.
Two Methods of Creating Transgenic Organisms
Gene Knoc Out & Gene Knock In
Gene Knock In
the process of creating a transgenic organism with new characteristcis by inserting a gene
Gene Knock Out
the process of creating a transgenic organism with less characteritics than originally by removing a gene
What process creates an organism with a new characteristic?
Gene Knock In
What process creates an organism that has lost an existing characteristic?
Gene Knock Out
Can both alleles be lost from a genome?
Yes.
What is a Knock Down?
Gene is silenced instead of removed
What is a construct?
a piece of engineered DNA
Homologous Recombination
DNA that is homolgous with the the wild-type DNA is included in the new construct with new DNA so that the construct will incorportate more easily into the organism.
Restriction Endonuclease
hydrolyzes nucleic acids within a sequence, but is restricted to only hydrolyzing certain locations on the seqeunce #findsspecifictargetbeforecutting
Endonuclease
hydrolyzes nucleic acids within a sequence
What 3 big things are needed for cutting & pasting to form recombinant DNA?
Restriction Enzymes
Ligase #Glue
Engineered Nucleases
What acts as “molecular scissors”?
Restriction Enzymes/Restriction Endonucleases
Class I Restriction Enzymes
recognize a sequence, but cuts ~1000 base pairs away
Class III Restriction Enzymes
recognize a sequence, but cuts ~20 base pairs away
What Class of Restriction Enzymes are used in by scientists in Recombinant DNA Technology?
Class II
Class II Restriction Enzymes
recognize a sequence of DNA and cuts right there #precise
Which class of restriction enzymes is the most precise?
Class II
HaeIII (Pronunciation & Name Breakdown)
Hey - 3
Hae = Haemophilus aegyptus
3 = this was the 3rd restriction endonuclease reconginzied from H. aegyptus
HindIII (Name Breakdown)
H=Haemophilus
in = influenzae
d = strain of H. influenzae
3 = 3rd endonuclease discovered in that strain of bacteria
What type of cut does HindIII make?
Cohesive Cut
What type of cut does HaeIII make?
Blunt Cut
Cohesive Cut
staggered cut
(leaves behind single-strandeded overhangs #stickyends)
*effective in attaching molecules with similar sticky ends.
Blunt Cut
straight cut through both strands of DNA
What do bacteria use restrcition endonuclease activity for?
Restriction endonucleases allow bacteria to protect themselves against viral DNA by cutting up the viral DNA.
What determines how frequently a restriction enzyme cuts?
How long or short the restriction sequence is.
The shorter the sqeuence, the more frequently it cuts. The longer the sequence, the more restricted it is and the less frequently it cuts.
Ligase
seals the sugar-phosphate backbone of DNA by creating phosphodiester bonds #glue
Can temperature affect restriction enzymes?
Yes
Because enzymes are proteins and can be denatured.
At what temp do most restriction enzymes work best?
37 C
Do restriction enzymes need cofactors?
Sometimes - depending on which enzyme.
5 Factors Affecting the Activity of Restriction Enzymes:
- temp (~37)
- presence of cofactors (i.e. Mg)
- conc. of ions
- pH (~7-8)
- methylation of DNA
Can nucleases be programmed to cut specific sequences in genome editing?
Yes
i.e. Meganucleases, ZFN, TALEN, Cas9
Which nuclease is the easiest to engineer?
Cas9
ZFN
Zinc Finger Nucleases
TALEN
Transcription Activator Like-Effector Nucleases